how do you normally get the mirror finish on sheeted models?

[OwenN]

My questions are getting lost in my longer thread, so I am starting a new one, on sanding sealer, grain filler,top coats, spray unit quality.

1) Is there an ongoing thread or "how-to" posting on this subject?

2) I haven't done this on a flying model before. my techniques for static models don't apply.

a) What is the balsa grain filler called? I saw sanding sealer, but not grain filler.
b) Do you use a special sanding undercoat? I was planning on partly blocking and filling the grain with epoxy, squeegeed on, under baking paper.
That stuff sands well, and it stiffens up the balsa.

c) What gloss coats and top coats do you use? I would have thought that some type of lacquer finish is needed, but I need to get it in
250 ml quantities, not 10ml , as I am used to. Who sells lots of colours in this size? Can it be sent internationally, or do you need a special license
and packaging for that?

d) In some areas, I think only 2-pack finishes are allowed (California?) - we can use solvents, here.
Are 2-packs easy to use, or cheaper?

e) What grade of spray gear do you use? Is Airbrush adequate, or do I need a big compressor and a can-type spraygun, and a big hose?
How much CFM, pressure horsepower? I/2 hp??, 2 cu ft tank?, 120 psi, regulator, water trap.

 

[TheFlyingBrit]

I assume your painting your balsa rather than covering in film ? May want to look at the weight difference between: adding filler, sealer, plus paint vs applying solar film or something similar.
Not sure if we are talking about the same 2 pack here. But in the UK, 2 pack fumes are toxic so you need full face respirator when spraying with that particular paint medium and you will need a special booth with extraction !
If you are intent on paint spraying your model, its worth looking at water based spray paint. Before you jump to conclusions, its not like kids poster paints, this paint is now used by car manufacturers, its very tough and durable with no health issues either.

 

[BATTLEAXE]

I hear regular household spackle works great as a gap filler, lightweight and easy to sand. Wood filler reduced down with water will be the one that goes over the spackle to smooth out the rest for covering or paint

 

[Monte.C]

My questions are getting lost in my longer thread, so I am starting a new one, on sanding sealer, grain filler,top coats, spray unit quality.

1) Is there an ongoing thread or "how-to" posting on this subject?

2) I haven't done this on a flying model before. my techniques for static models don't apply.

a) What is the balsa grain filler called? I saw sanding sealer, but not grain filler.
b) Do you use a special sanding undercoat? I was planning on partly blocking and filling the grain with epoxy, squeegeed on, under baking paper.
That stuff sands well, and it stiffens up the balsa.

c) What gloss coats and top coats do you use? I would have thought that some type of lacquer finish is needed, but I need to get it in
250 ml quantities, not 10ml , as I am used to. Who sells lots of colours in this size? Can it be sent internationally, or do you need a special license
and packaging for that?

d) In some areas, I think only 2-pack finishes are allowed (California?) - we can use solvents, here.
Are 2-packs easy to use, or cheaper?

e) What grade of spray gear do you use? Is Airbrush adequate, or do I need a big compressor and a can-type spraygun, and a big hose?
How much CFM, pressure horsepower? I/2 hp??, 2 cu ft tank?, 120 psi, regulator, water trap.

Did you read my answer on my thread yet?
https://forum.flitetest.com/index.p...-of-a-better-name-thats-why.65789/post-622378
This is the way I did it decades ago, and then how I modify it for planes today.
Weight is an issue.
One coat of filler just where you need it. Lightweight spackle.
Sand carefully.
(Do it again if you need to.)
Then one coat of spray paint, the brand of your choice.
And they all lived happily ever after. The end.

 

[TheFlyingBrit]

I have just invested in some acrylic based filler, which is light weight, sandable and flexible when dry. I keep you updated how I get on.

 

[Monte.C]

Oh if it's a balsa surface I might use a bit of wood filler first, then sand it out. Then proceed with the above.

 

[TheFlyingBrit]

Did you read my answer on my thread yet?
https://forum.flitetest.com/index.p...-of-a-better-name-thats-why.65789/post-622378
This is the way I did it decades ago, and then how I modify it for planes today.
Weight is an issue.
One coat of filler just where you need it. Lightweight spackle.
Sand carefully.
(Do it again if you need to.)
Then one coat of spray paint, the brand of your choice.
And they all lived happily ever after. The end.

Nicely put Monty keep that weight down
or is that what my wife keeps saying to me

 

[TheFlyingBrit]

The old french polishers trick was to dilute wood varinsh 50:50 with white spirit. coat the wood with that first so it soaks in and binds the fibres.
Sand back the surface with a fine grade paper, then clean of residual dust off with white spirit neat.
Then apply a second coat of 50:50 varnish/ white spirit and sand again. Clean the surface again to remove dust then you can fill any gaps and sand smooth. You can apply a varnish, laquer or bees wax for your final coats its up to you.

 

[Monte.C]

My friend, for heaven's sake don't go crazy. Again - like the boats I did - if you prepare the surface correctly with filling and sanding, then spray from a can will work perfectly well. Wow I wish I had pictures. I built an offshore deep-V that you would swear was an expensive fiberglass model. All perfect sharp corners & edges & curves. I think I'm captain of the Krylon fan club.

 

[OwenN]

I could use actual metal?? Flite-Metal adhesive tape. The model I am working on does not have well-recorded or laid-out
panel edges (semi-scale Rockwell XFV-12) I will check some photos and see if I can break the panels up reasonably.

https://www.modelairplanenews.com/s...ro-tips-for-applying-flite-metal/#outer-popup
Otherwise I have found 2-pack polyurethane gloss marine finish-that shouldn't be too fumy.
It is NZ $41 per 312 ml, which is not too bad for a unit price.

I have ordered a colour chart. A wholly aluminium model may be a bit dazzling to fly on a sunny day.

I was thinking signal red, with a white "V" underneath and a black "V" on top, to help identify orientation at 200 yards range!
I haven't had any luck with rattle-can paint-it is generally terrible stuff, shrinking and cracking.
Tamiya do a reasonable spray lacquer, but it would cost a bit to cover 50 x the usual area.
I have some sanding sealer I can try. I am keen to try boat epoxy, as it stiffens up the balsa, and sands quite well.

I will read through the replies above.

 

[Ketchup]

I could use actual metal?? Flite-Metal adhesive tape. The model I am working on does not have well-recorded or laid-out
panel edges (semi-scale Rockwell XFV-12) I will check some photos and see if I can break the panels up reasonably.

https://www.modelairplanenews.com/s...ro-tips-for-applying-flite-metal/#outer-popup
Otherwise I have found 2-pack polyurethane gloss marine finish-that shouldn't be too fumy.
It is NZ $41 per 312 ml, which is not too bad for a unit price.

I have ordered a colour chart. A wholly aluminium model may be a bit dazzling to fly on a sunny day.

I was thinking signal red, with a white "V" underneath and a black "V" on top, to help identify orientation at 200 yards range!
I haven't had any luck with rattle-can paint-it is generally terrible stuff, shrinking and cracking.
Tamiya do a reasonable spray lacquer, but it would cost a bit to cover 50 x the usual area.
I have some sanding sealer I can try. I am keen to try boat epoxy, as it stiffens up the balsa, and sands quite well.

I will read through the replies above.

A silver plane with a white v on the bottom and black on top would still be hard to see, and you would probably lose orientation or sight of the aircraft without going too far at the speeds you are planning to fly. Also 200 yards of range might seem like a lot, but at the 90 mph you were talking about you can use up that space real quick, and at those speeds lots of stuff will be hard to see. If I misunderstood what you meant and you actually meant using red all over with a white V on the bottom and a black one on top, then you will be able to see the plane, but you will need to ensure that the V's are big enough that you can easily tell the difference between top and bottom, and to make it easier front and back. Since you have never flown before (I think) I would suggest being able to also tell apart front and back. You might have gyros and computers flying the thing, but you can't do much if you can't see the plane.

 

[OwenN]

I assume your painting your balsa rather than covering in film ? May want to look at the weight difference between: adding filler, sealer, plus paint vs applying solar film or something similar.
Not sure if we are talking about the same 2 pack here. But in the UK, 2 pack fumes are toxic so you need full face respirator when spraying with that particular paint medium and you will need a special booth with extraction !
If you are intent on paint spraying your model, its worth looking at water based spray paint. Before you jump to conclusions, its not like kids poster paints, this paint is now used by car manufacturers, its very tough and durable with no health issues either.

Car manufacturers also stick the whole car in a bake oven!! - can't do with balsa.

A silver plane with a white v on the bottom and black on top would still be hard to see, and you would probably lose orientation or sight of the aircraft without going too far at the speeds you are planning to fly. Also 200 yards of range might seem like a lot, but at the 90 mph you were talking about you can use up that space real quick, and at those speeds lots of stuff will be hard to see. If I misunderstood what you meant and you actually meant using red all over with a white V on the bottom and a black one on top, then you will be able to see the plane, but you will need to ensure that the V's are big enough that you can easily tell the difference between top and bottom, and to make it easier front and back. Since you have never flown before (I think) I would suggest being able to also tell apart front and back. You might have gyros and computers flying the thing, but you can't do much if you can't see the plane.

No silver, just red, red border on wing, then white-20% wing, red again. It is a V because the wing is well swept-not quite delta in this XFV-12 version. I shall put smaller white Vs on the tail sides and fuselage sides, where the original had phantom markings.

Re: front and back-that would require different coloured markings on the wing leading and trailing edges, or maybe a brightly coloured nose? Paint yellow back to the cockpit?

Re : loss of control, I will address that in the setup. With no input, it will start to orbit. Then it will make overhead passes to reorient the operator.
If it is left alone for too long. or loses signal, it will return to base and land.

You may not be familiar with my previous discussions on my proposed aircraft specs.

It has auto -tailsitter logic built in, so it could practically "land on a sixpence"
-Ardupilot flight controller software.
Stationkeeping and wind drift control as well.
It borrows this from the better specced quadcopters.


The main thing is -if seems to be out of control and heading at the ground, leave it alone.

If I don't do anything risky close to the ground, it could recover on its own, given the space.
In theory it should never stay in a stall-spin, dive, or other upset flight condition

Well, I have been blabbing on too much about this.
Time to get back to finish drawing the revised 1/5 scale layout, then
restart the full size drawings again.

I shall scavenge the large wing plan details, then chuck that piece of paper out.

.

 

[OwenN]

I assume your painting your balsa rather than covering in film ? May want to look at the weight difference between: adding filler, sealer, plus paint vs applying solar film or something similar.
Not sure if we are talking about the same 2 pack here. But in the UK, 2 pack fumes are toxic so you need full face respirator when spraying with that particular paint medium and you will need a special booth with extraction !
If you are intent on paint spraying your model, its worth looking at water based spray paint. Before you jump to conclusions, its not like kids poster paints, this paint is now used by car manufacturers, its very tough and durable with no health issues either.

Apparently this 2-pot stuff is fumy, like full protective gear, respirator, goggles, gloves.

Standard poly resin is not that bad if you use it with plenty of ventilation, and limit exposure. This should be similar.
Not so good if you want to keep dust out.

Don't use it 8 hours a day, 5 days a week, without the gear.

Even rattle cans deserve some respect. Solvents can be a bit nasty in large doses, and you don't want to fill your lungs with plastic particles, even if relatively low toxicity.

It is formulated for airless sprayers, so may be able to be brush painted. I shall try.

Epoxy, which is generally non-toxic, will cause severe allergies if used continuously without full protective gear.

Here is a colour chart. Rescue Orange looks good for a base colour??

 

[Bricks]

All this paint and finishing is going to add considerable weight have you considered that, it might fly like a brick if it gets too heavy.

 

[OwenN]

At around 50 oz/sq ft, I expect it to handle rather like a large scale RC model warplane. -80 to 100 inch?

The paint and resin shouldn't be a lot heavier than sanding sealer, dope, and film.

The proposed model seems to have good reserves of thrust for the planned weight.
It won't need flaps to land because it is a "Prop Hanger".

The COG is well back, so it should just smoothly drop the tail as it slows down. It has tailsitter software, so that should rev up the motors to catch any nose drop.

Re: inverted, about 60 meters minimum altitude should give a little breathing room. Don't start a Bunt below 120 meters??
This thing is to be trimmed for flip-stops, so I can do that if heading down too fast. - at 30 gs braking, it should slow down quickly.

 

[OwenN]

There has been a comment, possibly in another thread, that they don't like using epoxy as it is much harder than the underlying material, and hard to sand flat.
This has to be addressed when you use epoxy.
Any excess has to be scraped off before it sets.
Coating the whole skin in epoxy and scraping back, or squeegeeing through a layer of baking paper, are other approaches.
Any mismatches and hollows have to be dealt with using filler.
Balsa filler is pretty light weight. It has to be sealed, as it is water soluble.

The aim is to end up with a sanding surface which is totally epoxy.-otherwise, you can be better off using balsa cement, sanding filler, and dope, or some type of woodworking glue.

I am not that keen on using a solvent glue, as it shrinks, and is only good where there is no possibility of gaps.

When you are skinning a model, you cannot get the surfaces to mate perfectly, and apply even pressure all over the curved surface.
Epoxy does a better job in this case.
I will investigate sucking the epoxy up into disposable syringes, to quickly apply an extruded glue bead.

I wonder how slow-set epoxy goes in this regard. Is it enough gell-like, or do I need to add gelling agent?
The 15 minute epoxy glue may go off too quickly when applying a wing skin???